Public employee drug testing programs may gain added impetus from two U.S. Supreme Court decisions which upheld postaccident drug and alcohol testing of railway employees after major train accidents. In addition, recent Federal executive and congressional initiatives are concerned with mandatory drug testing of Federal employees and workers in federally regulated industries, mainly transportation. The Department of Transportation (DOT) issued comprehensive regulations in 1988 that require industrywide testing of workers in the trucking, bus, rail, air, and maritime transportation industries. Executive Order 12564, issued in 1986, makes Federal executive branch employees in sensitive positions subject to mandatory drug testing. In addition, the Office of Personnel Management has issued guidelines on the establishment of a drug-free Federal workplace. The omnibus drug bill, P.L. 100-690, requires Federal contractors and grantees to certify they will maintain drug-free workplaces. Further, U.S. defense contractors must establish and maintain a drug-free workplace program under a 1988 Department of Defense regulation. In 1988, DOT published drug testing rules that affect public and private sector transportation employees in the aviation, motor carrier, railroad, maritime, mass transmit, and pipeline industries who hold safety- or security-sensitive positions. Congressional and judicial actions related to mandatory drug testing of transportation workers are noted. 62 footnotes